The short answer to your question is no, I don't know what happened, but I have noticed the same thing.

There were occasions in the past when the girls had trouble getting through immigration, and that issue has only become worse with the current state of paranoia.  Our government strikes another blow at the honest hobbyist.  Maybe the difficulty of border passage is a factor, or maybe there is enough business in Canadian cities to keep the girls north of the border and the agency owners happy.  Also, this activity, or at least outcall, is legal in Canada, and so there are few, if any, legal risks, compared to the US.

Anyway, whatever the reason, like you, I am missing those charming and sexy French-Canadian girls and the variety that they provide.

Montreal is a bit on the chilly side at this time of year, but you could always take a trip north.

DJ